/Engine/Source/Runtime/Engine/Classes/Kismet/BlueprintPathsLibrary.h
Converts a relative path name to a fully qualified name relative to the specified BasePath. BasePath will be the process BaseDir() if not BasePath is given
static [FString](API\Runtime\Core\Containers\FString) ConvertRelativePathToFull ( const [FString](API\Runtime\Core\Containers\FString) & InPath, const [FString](API\Runtime\Core\Containers\FString) & InBasePath )